The present invention generally relates to the field of ink jet printers and, in particular, to a method for refilling ink cartridges used with such printers.
A significant expense associated with the operation of ink jet printers is the cost of replacing the printer's ink cartridge once the cartridge's charge of ink has been exhausted. Over the lifetime of a printer, this cost can be substantial. The structural components of the ink cartridge, however, are quite durable and capable of far outlasting the cartridge's ink charge. As a result, discarding an ink cartridge simply because its ink charge has been expended is a wasteful, expensive practice.
Recently, the practice of recharging ink cartridges has become popular. In accordance therewith, rather than discarding a cartridge simply because its ink charge has been expended, the cartridge is recharged with a fresh supply of printing ink. However, this practice depends upon the type of ink cartridge needing recharging.
One method used to refill ink jet cartridges is to inject ink through an ink reservoir cavity breather port. Or, because the method is often messy and inefficient, another more effective way to refill these types of ink cartridge is through the device or method types described in the U.S. Pat. No. 5,199,470. The teachings in that pending patent application are incorporated herein by reference and show how to clear a hole in the expended cartridge reservoir and inject ink through a nozzle when an elastic, ink-filled cavity is squeezed by the user.
Nevertheless, these methods and apparatus are unsuitable for the newer and more efficient ink jet cartridges. Such cartridges typically include accumulators to accommodate variations in volume as the cartridge ejects ink or is exposed to other environments. The accumulators in these ink jet cartridges may include a bladder linked to ambient air pressure and connected to a volume-minimizing spring. Typically, the bladder resides at one pressure and expands or contracts to maintain operational back-pressure in the remaining portion of the cavity which contains the ink. Hewlett-Packard Company describes such a device in European Patent Application No. EP 04 37363 A2. The prior art refill methodology and devices do not consider this type of ink jet cartridge and will not work effectively.
It is therefore an object of the present invention to provide methodology for recharging ink cartridges. It is another object of the invention to provide a methodology for recharging ink cartridges with less ink spillage, and hence more economy, than known methods. It is another object of the invention to provide a method for refilling cartridges which contain bladder cavities or other similar ink jet cartridges. It is still another object of the invention to provide an improved method for recharging ink jet cartridges.